It is the aim of this research to characterize nucleotide sequences in ribosomal RNA (rRNA) both in terms of spatial and functional relationships. Knowledge of the role of rRNA within the ribosome is a prerequisite for complete understanding of protein synthesis, a process common to all degrees of complexity and development. It is necessary to fully understand basic life processes such as these so that we may see how they are altered in pathological and neoplastic cases. We have shown that regions of rRNA are conserved during evolution by methods of RNN-DNA hybridization and comparative fingerprint analysis. We are further characterizing these regions in terms of their primary structural location (by electronic microscopy of spread nucleic acids and by restriction enzyme (mapping), their secondary structure (by gel electrophoresis isolation of hairpin loops), and their tertiary structure in the ribosome.